The present invention relates to dialkylzinc compositions having improved thermal stability. More particularly, the present invention relates to compositions comprising a dialkylzinc compound in admixture with a stabilizer which reduces the thermal decomposition rate of the dialkylzinc compound.
Dialkylzinc compounds, particularly diethylzinc, are known to be useful as polymerization catalysts in Ziegler-Natta type systems, as chemical intermediates as well as alkylating agents. In addition, diethylzinc has been found useful as a preservative for paper, which can be applied to existing books and the like to extend their useful life, as is reported in the October 1979 issue of "Chemical and Engineering News".
Unfortunately, however, the dialkylzinc compounds in addition to being pyrophoric and highly reactive with water, are thermally unstable and can decompose rapidly at elevated temperatures. The decomposition is exothermic, and could therefore become a "runaway reaction" unless special precautions are taken to prevent it. Thus, for example, a quantity of this material in storage could slowly increase in temperature, due to slow decomposition, until a point was reached where the decomposition rate increased to a level which could present a hazard.
It has been reported, for example, that the half-life of diethylzinc is 10 days at 120.degree. C., about 1 day at 150.degree. C. and only a few minutes at 200.degree. C.
The thermal instability of these compounds has been a significant deterrent to their use because measures required to prevent the possibility of a runaway reaction sometimes outweigh the benefits to be achieved.
If, however, the dialkylzinc compounds could be stabilized against thermal decomposition so that their decomposition rates were more manageable, the use of these compounds would be far more attractive.
A need therefore exists for a method by which the thermal decomposition rates of dialkylzinc compounds can be reduced.
It has now been found that the addition of acenaphthene compounds to dialkylzinc compounds substantially reduces their rates of thermal decomposition.